The artificial capillary cell culture technique provides a pericellular microenvironment that closely resembles the in vivo state. This may allow normal cells to maintain their differentiated functions for prolonged periods of time in vitro. Cells are maintained in a physiologic state without many of the artifactual conditions imposed by standard methods of tissue culture. The technique is, therefore, especially well suited for the culture of cells of endocrine origin. Response of the cells to various physiologic agents are being studied as well as the secretion of various hormones over long periods with the possible application to continuous production of hormones for laboratory and clinical uses.